Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753425AbeADPt3 (ORCPT + 1 other); Thu, 4 Jan 2018 10:49:29 -0500 Received: from mail-wm0-f54.google.com ([74.125.82.54]:36817 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753315AbeADPt1 (ORCPT ); Thu, 4 Jan 2018 10:49:27 -0500 X-Google-Smtp-Source: ACJfBotrBbGAevzyIEvVsB8Apy/bZk+PEhTLX9SgHR+ziLjXZ91yJ76KKiqlXM9K3jS6esbsVkG9Zg== MIME-Version: 1.0 In-Reply-To: <9c6cddb9eb16a8c4bdab2e66c072b2bc9a10fcd4.1513609024.git-series.maxime.ripard@free-electrons.com> References: <9c6cddb9eb16a8c4bdab2e66c072b2bc9a10fcd4.1513609024.git-series.maxime.ripard@free-electrons.com> From: Chen-Yu Tsai Date: Thu, 4 Jan 2018 23:49:04 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 09/12] drm/sun4i: backend: Add a custom atomic_check for the frontend To: Maxime Ripard Cc: Daniel Vetter , David Airlie , dri-devel , linux-kernel , linux-arm-kernel , Thomas Petazzoni , Neil Armstrong , thomas@vitsch.nl Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Mon, Dec 18, 2017 at 10:57 PM, Maxime Ripard wrote: > Now that we have everything in place, we can start enabling the frontend. > This is more difficult than one would assume since there can only be one > plane using the frontend per-backend. > > We therefore need to make sure that the userspace will not try to setup > multiple planes using it, since that would be impossible. In order to > prevent that, we can create an atomic_check callback that will check that > only one plane will effectively make use of the frontend in a given > configuration, and will toggle the switch in that plane state so that the > proper setup function can do their role. > > Reviewed-by: Neil Armstrong > Signed-off-by: Maxime Ripard Reviewed-by: Chen-Yu Tsai